Inhalation device

ABSTRACT

An inhalation device for inhalation of a pharmaceutically active substance from a reservoir in an inhaler comprising an inhalation channel with an air inlet and an air outlet, said device comprising a dispersing chamber having an air inlet and an air outlet into which the active substance may be sucked from said reservoir through the air outlet and means for allowing a user to inhale the active substance from said dispersing chamber, said dispersing chamber being defined by at least a first non-movable element and a second movable element, said second element being substantially cylinder-formed, said first element being arranged in said second element whereby a vacuum or negative pressure is created in said dispersing chamber when said first and second elements are moved in relation to each other, wherein said first non-movable element is fixed on the inhaler so that the second element will move in relation to both the first element and the inhaler when the device is activated for inhalation. The invention also relates to a method of dispersing a pharmaceutically active substance in a dispersing chamber by creating a negative pressure or vacuum in said dispersing chamber.

This application is a 371 of PCT/SE 95/01539 filed Dec. 12, 1995.

The present invention relates to an inhalation device for inhalation ofa pharmaceutically active substance from a reservoir in an inhalercomprising an inhalation channel with an air inlet and an air outlet,said device comprising a dispersing chamber having an air inlet and anair outlet into which the active substance may be sucked from saidreservoir through the air outlet and means for allowing a user to inhalethe active substance from said dispersing chamber, said dispersingchamber being defined by at least a first non-movable element and asecond movable element, said second element being substantiallycylinder-formed, said first element being arranged in said secondelement whereby a vacuum or negative pressure is created in saiddispersing chamber when said first and second elements are moved inrelation to each other.

The inhalation device according to the invention is preferably abreath-actuated dry-powder inhaler, containing multiple doses of amedicament containing an active substance, the inhaler havingmaneuvering unit for loading one dose of the medicament to a dosing unitand providing said dose in a position for inhalation. An inhaler of theprescribed type is described in EP-A-0 069 715 and EP-A-0 237 507.

The device according to the invention is especially designed forpatients who are not able to actively inhale or who are not able tocreate the inhalation flow necessary to release and lift the dose of thesubstance into the inhalation channel and to the lungs when using abreath-actuated inhaler.

BACKGROUND OF THE INVENTION

Inhalable pharmaceutically active substances are generally used fortreatment of diseases in the bronchial and pulmonary area, such asasthma and chronic bronchitis. Various embodiments of inhalation devicesor apparatus are used for the purpose. The function of these knowndevices depends on the creation of an airflow through the inhalationdevice caused by an inhalation by the patient. The airflow causes activesubstance to moved from a release position into the airflow in which itis dispersed. A specially advantageous inhaler of the above mentionedtype is the dry-powder, breath-actuated multidose inhaler TURBUHALER®,schematically described in the above mentioned EP-patents.

Some patients such as small children and elderly people with diseases inthe bronchial area are not able to use a breath-actuated inhaler as itmight be hard or even impossible for these patients to achieve thenecessary inhalation flow and these patients are today reduced to theuse of inhalers using pressurized gas, i.e. freon. Such inhalers sufferfrom many known disadvantages, such as unwanted side effects.

Furthermore, it is presently a problem to administer an Inhalablesubstance to an asthma patient who is anesthetized during an operationand the patient can not actively inhale. For many asthmatic patients theadministration of asthma pharmaceuticals during an operation is vital.

PRIOR ART

In order to facilitate the inhalation of pharmaceutically activesubstances being administered by the use of pressurized metered doseinhalers, so called PMDIs, it is known to provide expansion chambersinto which the substance, with the pressurized gas, is dispersed. Thesedevices are generally called spacers and a typical spacer is known fromGB 1 565 029.

Furthermore, inhalation devices including dispersion chambers have beendeveloped for breath-actuated dry-powder inhalers of the above mentionedtype. Such an inhalation device is described in EP-A-0 548 152. Thisdevice is however bulky and contains several mechanical parts whichmakes the device complicated and expensive to produce and to use. Thereliability is not very high due to the complexibility of the device.

SUMMARY OF THE INVENTION

The present invention relates to an inhalation device of the abovementioned type which can be used by patients having reduced ability tocreate an inhalation flow necessary to lift the dose from the releaseposition into the inhalation channel when using a breath-actuatedinhaler, and which can be used to administer Inhalable substances to apatient being anesthetized.

The invention provides a device which facilitates the use of especiallya TURBUHALER® for patients presently being reduced to the use ofpressurized metered-dose inhalers.

The inhalation device according to the invention has a non-complicatedconstruction with few mechanical parts, is simple and cheap to produceand is easy to use by the patient.

In the device according to the invention a first non-movable element isfixed on the inhaler so that a second element will move in relation toboth the first element and the inhaler when the device is activated forinhalation.

Further advantages with the present invention are clear form thedepending claims 2 to 16.

The present invention also includes a method of dispersing apharmaceutically active substance, in a dispersing chamber by creating anegative pressure or vacuum in said dispersing chamber by using a deviceaccording to the invention. The dispersed substance could thereby beinhaled using an ordinary inhalation flow or it could be pressed outfrom the inhalation device.

BRIEF DESCRIPTION OF THE DRAWINGS

The inhalation device according to the present invention will now bedescribed by way of example with reference to the appended drawings, inwhich

FIG. 1 shows a schematic view of a section of the inhalation deviceaccording to a first embodiment of the invention; and

FIG. 2 shows a schematic view of a section of the second embodiment ofthe inhalation device according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The device according to the invention is intended to be used inconnection with an inhaler for inhalation of a pharmaceutically activesubstance, e.g. the breath-actuated, dry-powder, multidose inhaler 12sold under the trademark TURBUHALER® . The inhalation device accordingto the invention may be modified within the scope of the appended claimsto be used with any dry-powder inhaler which when activated positions adose of the medicament in a release position in the inhalation channel.

Referring to FIG. 1, the preferred inhaler 12 is provided with areservoir for storing the substance, a metering or dosing unit, and aninhalation channel having an air inlet and an air outlet. The inhaler isalso provided with operating means comprising a maneuvering unit 13 formoving a metering device from a loading position in which apredetermined dose of the substance to be inhaled is metered into themetering device and a release position where the dose is placed in theinhalation channel, released and carried by the inhalation air throughthe channel to the air outlet or mouthpiece 15 of the inhaler.

As can be seen in the drawings the inhalation device according to theinvention comprises a first substantially non-moving element 10 which isprovided on the air outlet or mouth piece 15 of the inhaler. The firstelement 10 is formed as a piston having an opening 26 which, when thepiston is arranged on the air outlet of the inhaler, coincides with theopening 11 of the air outlet. The connection between the air outlet ormouth piece 15 of the inhaler and the piston is air tight through asealing or as in the preferred embodiment the piston is rigidly mountedon the outer walls of the air outlet or mouth piece 15 of the inhaler inorder to prevent air from entering between the two parts. The pistoncould be glued, welded or rigidly fastened in any other manner to theinhaler.

Around said first substantially non-moving element, i.e. the piston 10,a movable second element 6 is provided. Said second element 6 is hollowand substantially formed as a cylinder. In the upper part of thecylinder the walls merge and define a cone-shaped part 28. Above thiscone-shaped part 28 a further cylinder 22 having a smaller diameter thanthe cylinder 6 defining the second element is arranged. Said cylinder 22defines the air outlet of the dispersing chamber 20 and the inhalationdevice and is formed as a mouth piece or nose adapter part.

The piston 10 is arranged inside the cylinder 6. The piston therebydefines the bottom of the second element 6. A dispersing chamber 20 isdefined in the cylinder 6 above the piston 10. Sealing means 8 areprovided between the first and second elements at their mutual area ofconnection. The sealing means 8 are preferably provided as an O-ringsealing member and could be arranged in a groove provided on the outersurface of the piston.

As mentioned above the piston 10 is formed with an opening 26 whichcoincides with the opening 11 of the air outlet or mouth piece 15 of theinhaler. First valve means 18 are provided regulating the air flowthrough the air outlet and the opening in the piston to the dispersingchamber 20. The valve means are provided as a one way valve arranged toonly open when the air flows from the inhaler to the dispersing chamber.The valve could be of any known type and is in the preferred embodimentformed as a thin membrane of which one part is fixed to the wall of thepiston and the other end is free moving.

The cylinder 6 is formed with a limiting wall member 14 having an outletopening coinciding with the air outlet of the inhaler. The wall member14 defines the upper restriction of the dispersing chamber 20 and isprovided with holding means 30 for holding the inhaler in a fixedposition in relation to the rotation when the maneuvering unit 13 isrotated. These means could be provided as a ratchet mechanism, as teethrings or have any other construction. Second valve means 16 are providedin said opening for regulating the air flow out from the dispersingchamber upon inhalation of a user. A mouth piece 22 or nose adapter isprovided at the end of the cylinder 6.

The first and second valves 18 and 16 are preferably of similarconstruction and must be sensitive and easy to open in order to minimizethe inhalation flow resistance and retention of substance within theinhalation device. For this purpose the valves could preferably be madeas thin membranes of plastic or the like. The membranes could be fixedat one end in the opening of the piston 10 and the wall member 14respectively, as can be seen in the figure. The wall member 14 acts as avalve seat for the valve 18.

In a first preferred embodiment a further hollow cylinder element 4 isprovided. The cylinder is defined by a bottom and wall parts and isopened in its upper region. The bottom of said further cylinder 4 isprovided with air inlet openings 5 communicating with the inside of saidfurther cylinder element 4. A mounting element 24 for the inhaler isprovided inside said further cylinder and fixed to the bottom of thecylinder. The mounting element 24 comprises a portion 23 adapted to theform of the maneuvering unit 13 of the inhaler in order for it to befixedly mounted in said mounting means 24.

Due to this fixed and rigid mounting of the maneuvering unit 13 of theinhaler 12 in the mounting part 23 the unit 13 is rotated an angleproportional to the rotation of the outer cylinder-formed element 4. Therotation of the outer cylinder-formed element 4 and thereby themaneuvering unit 13 activates the inhaler 12 for inhalation as themaneuvering unit places the dosing unit and thereby a dose in therelease position within the inhalation channel.

The function of this embodiment will now be described.

In the inactive position, which is shown in FIG. 1, the innercylinder-formed element 6 is totally interposed into the outercylinder-formed element 4. When the outer element 4 is turned themaneuvering unit 13 and the dosing unit of the inhaler is turned and adose is placed in release position in the inhalation channel. The twocylinder formed elements 4 and 6 are thereafter moved axially inrelation to each other whereby the inhaler 12 with the piston 10 ispressed downwards along the inner wall of the inner element 6. Alow-pressure or vacuum is created in the dispersing chamber 20 when theelements are moved away from each other. The second valve 16 closes.

The valve 18 opens and air is drawn into the inhalation device throughthe air inlets 5 in the bottom part of the outer element 4. When the airpasses the inhaler, the dose placed in the inhalation channel isreleased and dispersed into the dispersing chamber 20.

The dispersed substance can now be actively inhaled by the patient, amethod which could be used also by small children, elderly people andothers with reduced inhalation capacity .

Alternatively the substance can be forced out of the dispersing chamber20 by pressing the piston 10 and the second element 6 together againafter the activation and dispersion of the dose has taken place. Thevolume in the dispersing chamber will then decrease and an over pressureor positive pressure will be created. The valve 18 will open andair/substance contents of the dispersing chamber 20 will be forced outthrough the mouth piece 22 of the device. In this manner substance canbe forced down into the lungs of the patient. This active pressing outof the substance is especially intended to be used when treating ananesthetized patient but could also be used under other circumstances,e.g. by small children or elderly people refusing to inhale.

Referring to FIG. 2, the inhalation device could also be constructedwithout the outer cylinder 4.

A biasing element 32 is thereby provided between the piston 10, which ismounted on the mouthpiece and/or upper part of the inhaler, and thecylinder 6. The cylinder 6 is provided with stop means 35 provided atthe opened end of the cylinder preventing the cylinder from beingseparated from the piston 10. Further sealing means 34 are providedbetween the piston 10 and the inhaler 12. In this embodiment in theinactivated position of the device the piston 10 is arranged in relationto the cylinder in such a manner that the dispersing chamber has itslargest volume, i.e. the piston and the cylinder are in the retractedposition in relation to each other. When the device is activated forinhalation a dose is placed in the inhalation channel by the rotatingmovement of the maneuvering unit 13, which in this embodiment is handleddirectly by the user. The piston 10 is then moved within the cylinder 6,i.e. the piston is pushed towards the outlet of the cylinder 6, againstthe force of the biasing element 32. The volume of the dispersingchamber is decreased. The piston 10 is then released and will due to theforce of the biasing element travel instantly towards the bottom of thecylinder thereby creating a negative pressure or vacuum in thedispersing chamber as the volume increases. The dose will be sucked withthe air entering into the air inlets of the inhaler to the inhalationchannel and further up to the dispersing chamber. When the pressure hasbeen compensated the valve 18 will close and the user can inhale throughthe mouth piece as described above.

Further sealing means could be provided in order to secure an airtightsealing between the inhaler 12, the piston 10 and the cylinder 6.

The biasing element 32 is preferably a spiral spring but any other typeof resilient element could be used.

The use of the device to force the dose to be inhaled down into thelungs of a patient as described above could of course also be used witha device constructed in accordance with the second embodiment of theinvention.

The volume of the spacer could be varied due to requirements and needs,and a preferred maximum volume of the dispersing chamber is between50-250 ml.

The different parts of the inhalation device are preferably made ofplastics, metallized plastics or metal but other materials are alsopossible.

The present invention is preferably directed to the use of apharmaceutically active substance in powdered form wherein the powder isdispersed into the dispersing chamber 20 of the inhalation device in afinely divided form wherein the particles are smaller than 10 μm,preferably smaller than 3 μm.

POSSIBLE MODIFICATIONS OF THE INVENTION

The inhalation device according to the present invention could bemodified within the scope of the appended claims.

In the preferred embodiment the means for generating the negativepressure or vacuum are two cylinder-formed elements providedtelescopically in relation to each other. In the preferred embodimentthe elements have a circular cross-section but any other form such assquared is possible.

In the second embodiment a further cylinder could be provided in thesecond element 6. Said further cylinder is arranged to be separatelymovable in relation to the second element 6, whereby the biasing meansare provided in a space between the two cylinders.

I claim:
 1. An inhalation device for connection to an inhaler having apharmaceutically active substance in a reservoir of said inhaler whenconnected to the inhalation device, the device comprising:a firstelement that has connecting structure adapted to be connected to theinhaler, such that air drawn from the air outlet of the inhaler passesthrough said first element; a second element slidably connected to saidfirst element; a dispersing chamber, defined by said first element andsaid second element and having a outlet with a valve element permittingflow of air and said substance out of said chamber to a patient butpreventing flow of air into said chamber, the relative movement of saidfirst element and said second element being capable of increasing thevolume of said dispersing chamber and decreasing pressure by closingsaid valve element therein so as to draw air through and from saidinhaler with said substance entrained therein into said dispersingchamber.
 2. The inhalation device of claim 1, further comprising asealing member to create a seal between said first element and saidsecond element.
 3. The inhalation device of claim 1 wherein saidconnecting structure of said first element has an opening sized andshaped to mate with the air outlet of the inhaler to which the airoutlet of the inhaler is fitted with an air-tight seal.
 4. Theinhalation device of claim 3 wherein the opening in said first elementis in direct alignment with an opening of the air outlet of the inhaler.5. The inhalation device of claim 1, further comprising a first valveconnected to said first element, said first valve designed to open whenthe relative movement of said first element and said second elementcreates a decrease in pressure in said dispersing chamber and air isdrawn through the inhaler into said dispersing chamber, said first valvebeing designed to close when the relative movement of said first elementand said second element creates an increase in pressure in saiddispersing chamber.
 6. The inhalation device of claim 1 wherein theinhaler is a conventional dry-powder inhaler.
 7. The inhalation deviceof claim 6 wherein the inhaler has a manoeuvering apparatus, saidmanoeuvering apparatus including a dosing unit and a dosing disc, forfeeding a dose of the pharmaceutically active substance from a loadingposition to a position for inhalation in the inhalation channel of theinhaler.
 8. The inhalation device of claim 7 wherein the breath-actuateddry-powder inhaler is a TURBUHALER inhaler.
 9. The inhalation device ofclaim 1 wherein the first element is rigidly mounted on the air outletof the inhaler.
 10. The inhalation device of claim 7, further comprisinga sleeve surrounding said second element, said sleeve being rotatablerelative to said second element, and said sleeve capable of beingconnected to the inhaler.
 11. The inhalation device of claim 10 whereinthe manoeuvering apparatus is fixedly connected to said sleeve, so thatrotation of said sleeve relative to said second element causes rotationof the manoeuvering apparatus of the inhaler and positions a dose ofpharmaceutically active substance for inhalation.
 12. The inhalationdevice of claim 1, further comprising a biasing element between saidfirst element and said second element.
 13. The inhalation device ofclaim 12 wherein said biasing element is a spiral spring.
 14. Theinhalation device of claim 1 wherein said first element is in the formof a piston.
 15. The inhalation device of claim 2 wherein said sealingmember is an O-ring.
 16. The inhalation device of claim 15 wherein saidO-ring sealing member is arranged in a circular groove provided along anouter surface of said first element.
 17. The inhalation device of claim1, further comprising a final air outlet through which a user may accessair with said pharmaceutically active substance entrained therein fromsaid dispersing chamber.
 18. The inhalation device of claim 17 whereinsaid final air outlet of the device comprises a mouth piece or noseadapter.
 19. The inhalation device of claim 17 wherein a further conicalregion connects said dispersing chamber to said final air outlet. 20.The inhalation device of claim 3 wherein said opening of said firstelement sized and shaped to mate with the air outlet of the inhaler hasa generally conical shape.
 21. An inhalation device for connection to aninhaler having a pharmaceutically active substance in a reservoir ofsaid inhaler when connected to the device, the device comprising:a firstelement that is connected to the inhaler, such that air drawn from theair outlet of the inhaler passes through said first element; a secondelement slidably connected to said first element; a dispersing chamber,defined by said first element and said second element, the relativemovement of said first element and said second element being capable ofincreasing the volume of said dispersing chamber and decreasing pressuretherein so as to draw air with said substance entrained therein fromsaid inhaler into said dispersing chamber; a first valve connected tosaid first element, said first valve designed to open when the relativemovement of said first element and said second element creates adecrease in pressure in said dispersing chamber and air is drawn throughthe inhaler into said dispersing chamber, said first valve beingdesigned to close when the relative movement of said first element andsaid second element creates an increase in pressure in said dispersingchamber; a second valve connected to said second element, said secondvalve designed to close when the relative movement of said first elementand said second element creates a decrease in pressure in saiddispersing chamber and air is drawn through the inhaler into saiddispersing chamber, said second valve being designed to open when therelative movement of said first element and said second element createsan increase in pressure in said dispersing chamber.
 22. The inhalationdevice of claim 21 wherein said first and second valves are designed toopen when a user draws a breath through the air outlet of the inhaler.23. The inhalation device of claim 22 wherein said first and secondvalves are formed as thin membranes fixed at one end to said firstelement and said second element, respectively, and freely moveable atthe other end.
 24. A method of preparing a dose of pharmaceuticallyactive powdered substance for inhalation therapy comprising the stepsof:providing an inhaler, said inhaler containing the pharmaceuticallyactive powdered substance; providing an inhalation device, saidinhalation device having a first element that has connecting structureadapted to be attached to said inhaler, a second element slidablyconnected to said first element, a dispersing chamber defined by saidfirst element and said second element, and an outlet with a valveelement permitting flow of air and said substance out of said chamber toa patient but preventing flow of air into said chamber; connecting saidinhaler to said inhalation device; moving said first element and saidsecond element relative to each other so that the volume of saiddispersing chamber increases and creates a decrease in pressure byclosing said valve element therein, which decrease in pressure draws airthrough and from the inhalation channel and activates said inhaler,thereby dispersing the pharmaceutically active powdered substance insaid dispersing chamber.
 25. The method of claim 24, further comprisingthe step of forcing the air and the dispersed pharmaceutically activepowder out of the inhalation device through said mouthpiece.
 26. Themethod of claim 25 wherein the step of forcing the air and dispersedpharmaceutically active powder out of the inhalation device through saidmouthpiece is achieved by moving said first element and said secondelement relative to each other so that the volume of said dispersingchamber decreases and creates a positive pressure therein.